1. Related Technical Fields
Related technical fields include touch panel operation devices, touch panel operation methods, and computer programs for performing a selection operation of a selectable object using a touch panel.
2. Related Art
Conventionally, devices provided with a liquid crystal display such as in-vehicle navigation devices, portable information equipments including PDAs (Personal Digital Assistant) and cellular phones, portable music players, portable game devices, personal computers, and the like are likely to have a touch panel on the front face of the liquid crystal display to accept a user's operation. The devices provided with a touch panel display selectable objects such as buttons and the like on the liquid crystal display. If the devices detect that a user has touched the position corresponding to a displayed selectable object, the devices execute processing for selecting the selectable object
In the processing for selecting the selectable object on the devices provided with the touch panel, the selectable object basically continues selected from when a “touch-on” where a state in which the user is not touching the touch panel transits to a state in which the user is touching the touch panel has been detected to when a “touch-off” where the state in which the user is touching the touch panel transits to the state in which the user is not touching the touch panel has been detected. A scroll operation of the selectable object can be executed by moving (dragging) the touching position with the selectable object continued selected.
The touch panel here employs a system such as a resistive system (a pressure sensitive system), a capacitance system, or the like. The touch-on and the touch-off are detected based on a change in pressure or capacitance generated when a part of the user's body (for example, a finger) or a pen has touched the touch panel. When performing the above-mentioned scroll operation, the finger of the user or the like may temporarily lift up from the touch panel against the user's intention or the pressure the touch panel is being pressed may be reduced while dragging. If the touch-off is determined in such case, the scroll may be stopped against the user's intention. The reason will be described below.
For example, FIG. 13 illustrates a scroll operation to scroll a map image 102 in a direction of an arrow 103 when the map image 102 displayed on a liquid crystal display 101 of a navigation device is being selected. In the scroll operation, the user performs a touch-on at a coordinate X1 displayed on the map image 102 and drags by moving the finger along the arrow 103. Here, if the finger of the user or the like temporarily lifts up from the touch panel or the pressure the touch panel is being pressed is reduced at a point X2 while dragging, the touch-off may be determined at the point X2. As a result, the selection of the map image 102 is canceled at the point X2 and the scroll is terminated. Further, a new touch-on is detected at a point X3 that is in the vicinity of the point X2. Thereby, a button 104 placed in an area including the point X3 where the touch-on was detected is selected against the user's intention.
Especially, the above-mentioned problem is likely to occur in touch panels employing a resistive system. Because the touch-off is detected against the user's intention when the pressure the touch panel is pressed decreases, even if the finger of the user or the like continues touching the touch panel.
In order to solve the above-mentioned problem, the following method is considered. The touch-off is not determined immediately after the touch-off was detected. That is, after the touch-off was detected, if the touch-on is detected within a predetermined time period, the touch-off is not determined under the assumption that the selection continues. Only if the touch-on is not detected within the predetermined time period, the touch-off is determined. For example, Japanese Patent Application; Publication No. 2002-366286 discloses a technology that, in a key input processing device including a unit that detects ON/OFF of a key at a predetermined interval, an OFF of a key input is determined when two or more OFFs have been sequentially detected.